I've had a similar sort of thing on
Ebay
. The buyer started by opening a dispute, and I responded by offering a refund when/if the item was returned. Supprise supprie that was the last I heard. Though as the seller it is your responsibility to ensure the item is delivered as described. If you don't want to take the chance of it being damaged in the post insure it.
That said, If I bought something that proved to be faulty, I would be really p***ed if I couldn't get my money back. There is a way to guarantee that you cannot loose out as a buyer, but I won't post it on an open forum as it gives the chancers an extra wepon in ripping people off. If I know you though I'll happily explain by PM.